Epidermolytic Toxin (ET) producing staphylococci are associated with a spectrum of dermatologic responses to infection known as Staphylococcal Scalded Skin Syndrome (SSSS) or Toxic Epidermal Necrolysis. ET is a low molecular weight protein exotoxin produced by certain staphylococci. ET is responsible for the skin changes seen in this syndrome but to date, toxemia has not been demonstrated and the role of antibody in protecting patients from the skin changes has not been established. This project addresses 3 major areas: 1) Radioimmunoassay methods for the measurement of epidermolytic toxin and antibody to epidermolytic toxin will be developed. 2) Clinical studies of patients with SSSS will search for the presence of ET in skin and blood in the acute phase and ET antibody in the convalescent phase. ET antibody will be assayed in family members and in normal people of various ages. 3) Model infections in mice with ET producing staphylococci will be created to follow the early development of toxemia, determine the time and localization of ET in the skin and correlate the nature of the host response to infection with the amount of ET produced.